1) Field of the Invention
The present invention relates generally to subsurface aeration and drainage systems, and more particularly, to a combination pressure and vacuum valve assembly for maintaining atmospheric isolation of the subsurface system while separating water from air and draining the water out of the system.
2) Description of Related Art
Subsurface systems have been developed for removing water and aerating turf on sports fields and golf greens. A typical system is comprised of a network of interconnected drainage pipe located beneath a region of turf and a blower connected in such a manner that a partial vacuum or differential pressure can be created in the drainage network. Water drains from the network through one or more “outfall” pipes that transport water to an external discharge location. For instance, many greens have several outfalls that are defined by the location of drainage pipes beneath the green. Greens with several surface grades sloping away from a ridge, for example, are often plumbed with an outfall for each sloped region.
In the vacuum mode of operation, when water is removed as air is drawn down through a region of turf, water becomes entrained in the air stream and the mixture of air and water moves toward the blower. A device called a “water separator” is normally located between the drain pipe network and the blower, and it functions to separate the air/water mixture into two separate streams comprising an air stream to the blower and a water stream into the drainage outfall. There are several reasons why it is desirable to keep water from reaching the blowers. First, since the blowers are normally designed to move air, not heavy water particles, both efficiency and effectiveness are reduced when significant quantities of water become mixed in the air stream. Secondly, water tends to collect at low elevation regions or “saddles” in the pipes which reduces the effective cross section of pipe, thereby reducing air flow through the pipes and ultimately from the turf.
The blower system has a second mode of operation where pressure rather than a partial vacuum is applied beneath the green to cause air to flow up through the turf thereby aerating the root zone and moderating temperatures on the surface from the air stream that has been tempered by the substrate beneath the green.
In either the vacuum or the pressure mode, the pipe network beneath the region being treated must be isolated from atmospheric pressure. Without such isolation, there would be little or no pressure differential and the air path would tend to go between outfalls and the blower rather than through the turf to the blower.
Various forms of separators and valves have been developed to break the air-water mixture into two streams of flow and at the same time provide atmospheric isolation between the vacuum or pressure created by the blower and the discharge outfall. One such conventional separator consists of a barrel-chamber configured such that the water/air steam entering the chamber encounters a baffle that causes water to drop gravitationally to the bottom while air continues moving above the water level to a port near the top of the chamber that is connected to the blower. An important feature of conventional separators is a “J trap” pipe configuration connected to the bottom of the barrel and through which the water discharges from the barrel into the outfall pipe. The J trap serves to isolate the pressure or vacuum in the separator from the outfall pipe. As water accumulates in the vault and in the J trap beneath, it builds up enough pressure head to overcome the vacuum created by the blower at which point water flows out of the J trap, through the drain line to the discharge outfall. An example of such a system can be found in U.S. Pat. No. 5,507,595.
Proper function of the J trap depends upon sufficient water being held to counteract pressure or partial vacuums created by the blower in the separator. If the system is in the pressure mode, for instance, and the pressure level is 20 inches Water Gage (WG), then the out leg of the “J” trap must be greater than 20 inches to counter the blower pressure. In the vacuum mode the longer down leg must be approximately 20 inches longer than the outgoing leg in order to develop enough pressure to permit water to escape from the outgoing leg without filling the separator barrel. When the two modes of operation are taken into account, pressure and vacuum, the trap must be greater than 48 inches deep to properly isolate the blower vacuum pressure beneath the green from the atmospheric pressure in the drain line. The overall depth of the excavation required to install and cover a separator plus a J trap is approximately eight (8) feet.
Normally only one outfall of a multiple-outfall drain network beneath a green is connected through a separator to a blower. Additional or multiple outfalls in the same network must also be isolated from atmospheric pressure in order for the proper pressure or vacuum levels to be established within the drain-pipe network beneath the turf. Conventionally, J traps are also used for this purpose, and a golf green with, for example, three outfalls will typically employ three J traps with one located on a separator unit and one on each of the remaining two outfalls.
However, there are several problems with this type of arrangement. More specifically, during installation, deep excavation is required to install a separator with J trap or a J trap on a multiple outfall green. Installation crews can lay pipe and make reliable connections much more expeditiously where deep excavations are not required. Deep excavations require specialized equipment, such as back-hoes and the like, and equipment operators that are not needed for shallow trenching. The cost and time of installation increases when deep excavations are required.
Further, with regards to reliability, J traps, by design, have deep curved channels through which the water travels to the discharge outfall. These deep regions tend to collect sediment and become constricted or clogged flow channels. J traps must be inspected frequently, especially after new green installations, where “fines” tend to wash out of the turf and settle in J traps. Another problem is caused when the surrounding soil shifts after a J trap is installed and connected to a separator barrel. The relative displacement of the two tends to break or crack the J-trap fitting thereby permitting additional sediment and fines to enter the trap or to render the J-trap inoperable.
Accordingly, it is an object of the present invention to provide a turf playing surface aeration and drainage systems that does not require deep excavation for installation and which maintains atmospheric isolation of the system while separating water from air and draining the water out of the system.